SPF, which is short for Sender Policy Framework, is an email safety system, that is used to validate if an e-mail message was sent by a certified server. Employing SPF protection for a domain will prevent the counterfeiting of emails generated with the domain. In simple words: enabling this feature for a domain name creates a specific record in the Domain Name System (DNS) which includes the IP of the servers that are permitted to send e-mail messages from mail boxes using the domain. As soon as this record propagates globally, it exists on all DNS servers that route the Internet traffic. Whenever a new email message is sent, the initial DNS server it uses checks whether it originates from an accredited server. When it does, it's forwarded to the destination address, yet when it does not originate from a server listed in the SPF record for the particular domain, it's rejected. Thus nobody can mask an e-mail address then make it look as if you're distributing spam. This approach is also termed email spoofing.